diff --git a/dom.bs b/dom.bs
index 32e859d34..e58b744c9 100644
--- a/dom.bs
+++ b/dom.bs
@@ -5895,6 +5895,10 @@ dictionary ShadowRootInit {
 <a for="/">element</a> is <a lt="create an element">created</a>, all of these values are
 initialized.
 
+<p><a for=/>Elements</a> have an associated
+<dfn export id=concept-element-duplicate-attribute-present for=Element>duplicate attribute present</dfn>
+which is set to false unless otherwise specified.
+
 <p>An <a for=/>element</a>'s <a for=Element>custom element state</a> is one of
 "<code>undefined</code>", "<code>failed</code>", "<code>uncustomized</code>", or
 "<code>custom</code>". An <a for=/>element</a> whose <a for=Element>custom element state</a> is